Earth cutting tool



C. C. MERRICK EARTH CUTTING TOOL Dec. 29, 1953 2 Sheets-Sheet 1 Filed April 28, 1950 Char/es C/ar/r Merrick ATTOR N EYS Dec. 29, 1953 c. c. MERRICK 2,664,273

EARTH CUTTING TOOL Filed April 28, 1950 2 Sheets-Sheet 2 Elma/whom Char/es C/ar/r Merrie/r ATTORN EYS Patented Dec. 29, 195$ UNITED STAT! TENT OFFICE 8. Claims.

This invention relates .to .new and usefulimprovements in earth cutting tools.

The invention is particularly concerned 'with ,a tool for forming a boreor opening extending horizontally through earth sections, such-as undera railroad or highway, or in other locations where the cutting of an ordinary ditch is not feasible for the laying of pipe andother conductors. 'It is to be kept in mind. however,'that the invention is not limited to the forming of horizontal openings or bores, since it is applicable with obvious modifications to other types of bores or' openings.

It is one object of the invention to provide an improved earth cutting too1.which is simple and efifective in operation; and'with-which large-openings beneath or through sections of earth maybe formed with facility and speed.

A particular object of: the invention is toipro videan improved earth cutting tool which cuts and forms the earth as it passes therethrough, as contrastedto the type of tool which seeks to'compress or taremove entirely'a quantity of earth in one passage of a tool and hence encounters tremendous physical'stresses' and loads.

An important object of the invention is to provide an improved earth cutting :tool which cuts the earth formation into a plurality of sections and at the same time applies'pressure tosaid sectionsso as to compact the same and tocause the sectionsto adhere together as individual elements which may subsequently be forcedfrom the bore whichhas been formed.

A further important object ofthe invention is to providean improved cutting head for an earth "through earth sections where ordinarydrilling operations are. not. feasible.

A const ction des gned .tocarryout the. invention will be "hereinafter tidescribed together with" other features; of vthelinvention.

Theinventionwillrbe'mor readily understood from" a readingtof:thespecification and by reference to the'accompanyingidrawings, wherein examples of the invention are shown, and wherein:

Fig. 1 is a view in perspective of a cutter head "for an earth cutting tool constructed in accordance'with this invention and adapted to carry out the teachings of this'imethod,

Fig. 2 is :a cross sectional viewof th cutter head,

Fig. '3 is an enlarged, longitudinal, sectional view or the cutter' head,

Fig; 4' is a cross-sectional view .taken upon the line 4-4 of Fig. 3,

' Fig. 5 is an enlarged sectional view showing the mounting of the reaming foot,

Figs.6, 7, 8'and 9* are schematic views illustrating the-various-operations of the cutting tool and exemplifying thecarrying out of this method, and i desired to forma horizontal opening or bore.

In this case, the illustrated earth section is a highway road bed; but it is noted that the invention is equally applicable'to any other type of earthformation orsection, and is not necessarily limitedto an elevated'section, such as that illustrated,"since the lateral portions of the section may be exposed through the digging of ditches or pits, and need not be'previously exposed topermitutilization of this invention.

Many types of devices are presently available in a commercial'iorm for forcing pipe lengthwise, either away from the device or 'into the device, and such a me hanism is illustrated schematically at H in'Figs. 6Ithr0ugh 9. In carrying. out the first step of'the bore" forming operation. aisuitable pipe or elongate conductor iZiis fclosediat oneend byra cap l3,-and is, forced throughithe earth section iilby. means of the me'chanismil. ,Although.anysuitable type of capmay be used to close .the end of the pipe IE, it has beenfound that acap having a flat end is-desirable since ithis. less easily .deviated. from i.ts;-proper..-path. ,IndeecL-the. capidcould be omitted entirely and the pipe. i2. allowed tojfill withearth asait xpasses through the section E6. In generalythis is'not desirable, since the pipe would haveito .be. cleaned out before. it could be used. again-:01 would, have to' be discarded and new pipe: employed. Nevertheless, the important and-onlyeessential feature of the firststep is the forming of an opening A of relatively small diameter through the earth section IE3.

After the pipe i2 has been forced entirely through the earth section it and is projecting from the opposite side thereof, the cap i3 is removed, and the earth cutter head it, illustrated in Fig. 1, is connected to the projecting end of the pipe. The cutter head it includes an elongate central body is having provision for water courses to be described hereinafter and preferably being hollow. Ordinary metal pipe may conveniently constitute the body !5. The latter is threaded. at each end for connection with the pipe !2 and for reception of a suitable cap IS. A plurality or cutter fins l'i extend radially from the exterior or the body it, the fins being relatively elongate and substantially rectangular in shape, and being evenly spaced about the outer periphery of the body i5 as shown in Figs. 1 and 2. While the fins may be formed integrally with said body, they are preferably afiixed thereto by welding or other suitable securing means and extend lengthwise or longitudinally of the body throughout a major portion of its length. As shown in Fig. 3, the fins I? are wider at one end than at the other and taper lengthwise to a slight degree from their leading edges E8 to their trailing edges it. The leading edge of each of the iins is bevelled or sharpened to form a cutting edge, and the outer edge of each of the fins 1 similarly bevelled or sharpened at it, as illustrated. in Fig. 2. A cutting band 2| encompasses the trailing edges of the fins, having one edge substantially alined with the trailing edges is and being secured by welding or in any other suitable fashion upon the outer edges of the fins i? so as to extend a short distance lengthwise of said fins. The band 2! is substantially wedgeshaped in cross-section having its rearward edge, which is positioned substantially flush or in alinement with the trailing edges E9 of the fins i'i, relatively fiat and blunt, while its cutting edge, disposed toward the cutting edges it from the trailing edges I9, is relatively sharp and thin. The outer surface 22 of the band is substantially cylindrical, and is disposed parallel to the axis of the body l5. The inner periphery 23, however, of the band forms a portion of a cone having its axis co-incident with the axis of the body 55, and hence the longitudinal thickening of the cutting ring which provides the wedge-shaped crosssection thereof, is substantially all toward the axis of the body 55. Hence the openings 24 which are defined between each pair of the fins ii and encompassed by the band 2!, decrease in cross-sectional area as one moves from the leading edge of the cutting band to the trailing edge thereof.

A plurality of relatively small radial openings 25 are cut in the body l5, one of the openings being provided between each pair of the fins i! and being situated substantially intermediate the ends of said fins. Although, in the preferred form of the invention, the body i5 is formed of ordinary pipe and access is easily had from the pipe it through the bore of said pipe to the openings E5, it is pointed out that any suitable type or character of water-courses may be employed for conducting fiuid under pressure from the pipe E2 to the openings 25.

Following the forcing or driving of the pipe l2 through the earth section, the cutter head i4 is secured to the projecting end of said pipe i2, and then the action of the mechanism H is reversed to force the cutting head back through the earth section. At the same time, a suitable fitting 26 is connected into the pipe [2 and a fluid under pressure, normally water, is introduced into the interior of the pipe l2 and hence into the interior of the body l5. As the head I4 is pulled through the earth formation, the leading edges 18 of the fins H penetrate the walls of the opening A formed in the first step of the method, and form radial slits or cuts in said walls. Further, as the fins continue their passage through the earth, and because of their lengthwise taper, said slits or cuts are deepened until the earth encounters the cutting ring 2|. At this point, it is to be noted that the initial passage of the pipe l2 through the earth formation results in a compacting of the earth formation so that the walls of the opening A are substantially denser or more compressed than remote portions of the earth formation. This compressing action is continued by the passage of the fins it through the previously compacted earth, it being noted that the fins do not remove earth but merely push the same aside to permit their passage. The final compacting and the severing of the compacted earth from the surrounding formation is accomplished by the cutting ring 2i which severs from the surrounding earth formation the ribbons of earth partially formed by the passage of the fins ii. The severing occurs at the leading edge of the ring 2|, and as the ribbons of earth pass rearwardly through the openings 24, they are additionally compressed by the converging walls of said openings and exit from the opening in the form of an elongate ribbon or rod of roughly rectangular cross-section and with a greatly increased density and coherence due to the compacting actions to which the dirt has been subjected. Thus, when the passage of the cutting head [4 through the opening A has been completed, the opening has been enlarged to form a bore of larger diameter, which will be designated by the letter B, and a plurality of ribbons or rods C of highly compacted and compressed earth are lying within said opening B.

Following this step, the cutting head is is removed from the pipe i2 and replaced by a substantially cylindrical head or ram 2? which is pushed through the opening B by means of the pipe l2 and forces the elongate ribbons C therefrom. Since the ribbons or rods 0 have been greatly compacted, they lend themselves readily to this operation and are simply extruded from the opposite end of the bore B.

It is to be noted that this cutting operation, and the concurrent supply of water under pressure through the openings 25, does not result in the forming of a slurry or mud mixture, since the openings are small in diameter and since only a small quantity of water passes therethrcugh. The water functions simply as a lubrieating agent and prevents the earth from sticking to the fins ii and the cutting ring 2 i. The quan tity of water is not sufficient to soften or loosen the earth, and it does not adversely affect the dense and compact nature of the earth ribbons or rods C.

In some cases, it may be desirable to enlarge the opening B, either upwardly or downwardly in order to permit the positioning of a pipe or other conductor within said opening with a desired degree of pitch or fall. In this case, it is desirable to use the cutting shoe 28 shown in Figs. 5 and 10, and which includes a shank 29 having a foot 30 directed at right angles therefrom. A short section of pipe or other support 3! is provided for carrying the shoe 28, and is connected between the pipe [2 and the cutting head I t. The pipe 3! is provided with a pair of diametrically opposed transverse openings 32 within which the shank 29 is received, and a suitable set screw or bolt 33 is provided for holding the shoe in position within said openings. It is obvious that by means of a set screw, the shoe may be adjusted so as to project any desired distance laterally of the pipes I2 and 3|, and since the shoe bears upon the inner surface or wall of the bore 3, the cutter head I4 will be displaced a corresponding distance laterally with respect to the other side of said bore. When this assembly is passed through the bore, the cutting head will necessarily ream or cut additional quantities of earth from one side of the bore B, and said bore will be enlarged as desired.

It is further to be noted that openings of large diameter may sometimes be required, and that such openings may be too large to be cut by a single passage of the cutting head it due to the large quantities of power required to form such a large opening. In this case, it is desirable to provide the cutting head M in a number or variety of diameters, and to pass successively larger diameters of the cutting heads through the bore to enlarge the same to the desired diameter. In such case, it may be desirable to connect the head or ram 21 between the pipe l2 and the cutting head [4, so that said ram functions as a pilot and maintains the cutting head properly centered with respect to the bore being enlarged.

By means of the cutting structures herein set forth and the method herein disclosed, openings or bores are readily formed in earth locations without requiring the digging or cutting of a ditch through said formation, and lengths of pipe or other conductors may readily be passed through the bores so formed.

The foregoing description of the invention is explanatory thereof and various changes in the size, shape and materials, as well as in the details of the illustrated construction may be made, within the scope of the appended claims, without departing from the spirit of the invention.

What I claim and desire to secure by Letters Patent is:

1. An earth cutting tool including, an elongate central body, a plurality of radial cutters carried by the body, each radial cutter comprising an elongate plate having its inner longitudinal edge adjoining the central body, the plate extending radially outwardly from the body and having its outer longitudinal edge formed with a radiallyoutwardly facing cutting edge, and an annular cutter ring encircling the radial cutters at one end thereof, the outer longitudinal edges of the radial cutters adjoining the ring, and the ring being provided with an annular cutting edge facing longitudinally of the central body toward the cutting edges of the radial cutters.

2. An earth cutting tool including, an elongate central body, an annular cutter ring encircling the body and spaced therefrom, the ring having a circumferential cutting edge facing longitudinally of the central body, a plurality of radial cutters extending radially between the ring and the body so as to divide the space between the ring and the body into a plurality of earth-receiving passages, each of the radial cutters comprising an elongate plate having its inner longitudinal edge adjoining the central body and a redially-outwardly facing cutting edge on its outer longitudinal edge, the radial cutting blades projecting from the ring and extending longitudinally of the body in the direction in which the rin cutting edge faces.

3. An earth cutting tool including, an elongate central body, a plurality of cutter blades extending radially outwardly from the body, each of the cutter blades comprising an elongate plate having one longitudinal edge adjoining the central body substantially throughout the length of said plate and having a radially-outwardly facing cutting edge on its outer longitudinal edge, and a relatively short cutter rin el'lClICling the cutter blades and adjoining the outer longitudinal edges thereof, the cutter ring having a circumferential cutting edge facin longitudinally of the cutting tool, and the cutter blades extending from within the cutter ring in the direction in which the cutter ring cutting edge faces.

4. An earth cutting tool as set forth in claim 3, wherein the cutting edges of the cutter blades merge into the cutting edge of the ring.

5 An earth cutting tool as set forth in claim 3, wherein the portions of the blades extending from Within the cutter ring are progressively decreased in width to incline the cutting edges of the blades progressively nearer the axis of the central body.

6. An earth cutting tool as set forth in claim 3, a central support alined with the central body and connected thereto, and a shoe having an earth-engagingface and carried by the support, said shoe being spaced'laterally from the support to force the ring cutter to. cut in a laterallydisplaced path.

7. An earth cutting tool as set forth in claim 3, wherein the cutter ring is progressively increased in wall thickness from its cutting edge to its opposite edge.

8. An earth cutting tool as set forth in claim 3, wherein the cutter ring is progressively increased in wall thickness from its cutting edge to its opposite edge and the cutter blades terminate in the transverse plane of said opposite edge of the cutter ring.

CHARLES CLARK MERRICK.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 163,636 Cheadle May 25, 1875 602,339 Lawton Apr. 12, 1898 1,847,985 Sawyer Mar. 1, 1932 1,993,365 Engelbright et al. Mar. 5, 1935 2,074,003 Templeton et a1. Mar. 16, 1937 2,193,219 Bowie et a1 Mar. 12, 1940 2,234,451 Ransome Mar. 11, 1941 2,239,531 Laurie Apr. 22, 1941 2,274,107 Sweet Feb. 24, 1942 2,281,614 Ogran May 5, 1942 2,354,245 Corbosiero July 25, 1944 2,498,192 Wright Feb. 21, 1950 2,529,246 Detrick Nov. 7, 1950 

